Ultra high frequency oscillator



Dec. 27, 1949 H. J. M CARTHY 294929647 ULTRA HIGH FREQUENCY OSCILLATOR Original Filed June 12, 1943 2 Sheets-Sheet l 8 i9 12 1g 4 i9 #9 i0 3 9 .1? 21 L5- 142i 91 13 I I i3 a0 18 v INVENTOR.

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ATTORNEY as. 27, 194 J, MCQARTHY ULTRA HIGH FREQUENCY OSCILLATOR 2 Sheets-Sheet 2 Original Filed June 12, 1943 ATTORNEY Patented Dec. 27, 1949 ULTRA HIGH FREQUENCY OSGILEATOR.

Henry J. McCarthy, Danvers,.'Mass.,'assignor to Sylvania Electric Products-Inca, "Salem, "Mass, a corporation of Massachusetts Original application June .12, .1943, :*Serial No. 490,703. Divided and thisapplication August 13, 1946, Serial No.-.690,244

This invention relatesto electrical oscillation devices with particular reference to ultra high frequency or short wave oscillations.

An object of this invention is to provide improved means for supporting short wave'electrical oscillations, and method of making said means.

Another object is toprovide means in an oscillator, for maintaining the oscillation wavelength at an eiiectively constant value despite temperature variation.

"Other objects, advantages, and features will be apparent from the following specificationtaken in conjunction with the accompanying drawing in which:

Figure 1 is a perspective view of a tube embodying this invention;

Figure 2 is an exploded View of the structure of Figure 1; and

Figure 3 is a section view, in part, of the structure of Figure 1, illustrating the oscillatory circuit.

The general nature of the device embodying this invention is that of a tube for the generation of electrical short waves, having metal plates as part of an oscillation circuit, and grids mounted on the plates.

An important disadvantage in a tube of this nature has been the undesirable change in wavelength produced by the effect of heat variation on the plates. Dimensional or positional change in the plates or parts thereof, as a result of heat variation, tended to change the capacitance or inductance, or both, in the oscillation circuit, with resultant undersirable tendency to change the wavelength.

Another disadvantage has been that grids mounted on the plates before the sealing of the plates in the walls of the envelope, were liable to be damaged by, or collect impurities during, the sealing operation.

This invention obviates the above disadvantages by so forming the plates that heat variation causes opposing tendencies of movement therein and the wavelength is effectively maintained at a. constant value; and by sealing the plates in the glass envelope without the grids and providing grid assemblies and means for removably mounting them on the plates, whereby the grids may be mounted on the plates after the sealing operation of the plates to the glass envelope.

The illustrative embodiment of this invention as shown in the drawings provides a tube base I; a glass envelope having a lower portion 2, a central portion 3, and an upper portion 4; electrodes 5 and 6 for supporting an electron flow therebetween within the glass envelope; and a pairof metal plates 1 and 8 which are hermetically sealed in the wall of the glass envelope and which separate the portions 2 and 3 and 4 of the envelope wall;

2 Claims. (Cl. 315- 5) An oscillatorycircuit is provided by the plates land" 8-andtheir' connection housing 9 outside the glass "envelope "as the inductance; and the separation of-"the plates 1 and 8 within the envelope 'as the capacitance.

The flow of electrons between the electrodes 5 and 6 past the plates 1 and 8 sets up oscillations in the-'oscillatory circuit; These oscillations are picked up by-the lea'd 1'0 and provide short elec-: trical waves. Ordinarily, heatvariation' in the plates 'l' and8 broughtaboutthrough theoperation of thetube, would so affect the plates 1 and 8 as to vary the gap therebetween and consequently the capacitance of the circuit, as well as to vary the dimensions of the plates and the connection housing and consequently the inductance of the circuit. This action would undesirably change the wavelength provided by the circuit.

The plates 1 and 8 are provided with annular portions l I and I2 respectively, formed to counteract and effectively neutralize the tendency of heat variation to change the wavelength of the oscillatory circuit.

Plates 1 and 8 also have turned lips l3 and I4 respectively, defining central cylindrical openings in which grid units l5 and I6 are mounted, being held by clips struck from the plates, as at I! in plate 8.

Plates 1 and 8 are further provided with peripheral flanges l8 and I9 which define annular sections 20 and 2| to which the glass portions 2, 3, and 4 of the glass envelope are hermetically sealed. The flanges I8 and I9 provide a seatfor the annular connection housing 9, as at 22 and 23.

The pick up loop 24 of the lead 10 extends within the cavity formed outside the glass envelope between the plates 1 and 8 and within the connection housing 9. The sleeve 25 through which the pick up lead l0 extends, provides a second pick up lead.

The action of the temperature variation compensation arrangement is illustrated in Figure 3. With the metal plate 1 anchored to the glass envelope parts 2 and 3, the normal tendency, under the action of heat, is for the lip l3 to move in the direction of arrow 21. The formation of the annular portion ll of plate 1 as a depression in opposition to the direction of the lip [3 causes the central portion of the plate 1 to move bodily in the direction of the arrows 28, under the action of heat, and thus counteract and neutralize the movement of the lip l3.

It is desirable to slightly more than counteract the movement of the lip l3 to ofiset the effect of the dimensional change in the peripheral portions of the plates 1 and 8, and in the connection housing 9.

Thus through similar arrangement of the an- 3 nular portion 12 of the plate 8., therelation between the inductance and capacity of the oscillatory circuit remains such that the resultant wavelength is effectively maintained constant under the action of heat variation.

In assembling the tube of this invention the glass envelope portions 2, 3 and 4 are sealed to the plates 1 and 8 while the bottom of portion 2 and the top of portion 4 are open, and without the grid units [5 and I 6.

When the sealing in of the plates 1 and 8 has been completed, the grid units l5 and 16 are mounted on the plates I and 8 and clamped in place as by clips l1, and thereafter the glass portion 2 is sealed to base I and the glass portion 4 is sealed about the electrode lead 29.

This is a division of an application by Henry J. McCarthy, filed June 12, 1943, Serial No. 490,703, for Ultra high frequency oscillators and now U. S. Patent No. 2,413,364, granted Dec. 31, 1946.

What I claim is: a

1. An electrical short wave generator tube comprising a hermetically sealed glass envelope; a pair of electrodes in said envelope one at each end thereof for supporting an electron'flow therebetween; a pair of annular metal plates sealed transversely through the wall of said envelope and having spaced aligned openings within said envelope and between said electrodes in line with the path of said electron flow, each of said plates having spaced clips for holding a grid assembly; a grid assembly removably held in each of said openings by the spaced clips on the respective plates; each said assembly comprising a grid sup- REFERENCES CIT ED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,353,742 McArthur July 18, 1944 2,402,119 Beggs June 18, 1946 2,411,522 Chevigny Nov. 26, 1946 

